Im gonna throw this in here even though its mostly unrelated to tekkit ( though i find its worse in tekkit than elsewhere )
There seem to be some kind of Permission glitch with a combination of Technic mcpc+/cauldron and mcmyadmin.
A person will login and not have any permissions on the server, they'll be able to talk and build normally but not be able to use plugin commands /tp, /warp, /bal ect ect
I've traced the problem down to a duplicate user error that i can see in the mcmyadmin window, but does not show in the console window. (though it happens without mcmyadmin)
This problem also seems to have a side effect of ALSO keeping mcmyadmins user list filled with the affected players name when they've logged off, when used with tekkit ( but not other modpacks i've noticed )
Example : b-team
At first i thought it was a permissionsex problem ( there are several threads there about it in pex's forum ) but i don't think it has anything to do with pex.
-The problem is intermittent but happens very often even on a server with only about 10-20 avg people peak ( at approx 10-20 times a day )
-The permissions lost seem to be any given by plugins, all vanilla functions seem to work fine.
-A person CAN come onto the server first time that day and get the problem
-The best workaround is re-logging
I bring this up mostly because i brought up the tekkitcustomizer duplicate items problem to skuli ( he found it had to do with an inventory glitch in mcpc+ ), and he talked to md_5 and got that fixed ages ago.
Im hoping to luck out again.
-edit: clarity
-EDIT: i just found out md_5 is going to be REALLY busy because a bukkit dev filed a dmca notice. ignore my post T_T
Check sep 6 and 4 posts
http://cauldron.minecraftforge.net/
Bukkit's news post
http://forums.bukkit.org/threads/bukkit-its-time-to-say.305106/
Mojang's thoughts
http://forums.bukkit.org/threads/mojang-and-the-bukkit-project.309715/

From a server owner's perspective I NEVER liked EE anyway. Huge hassle,
and not only that. What little interest i've had has been whittled away by the incredibly long intervals between updates of the mod.
I probably wouldn't notice if it was removed.

I for one Actually like mmpowersuits ( for what little time we have left with it ) you know, besides the fact that its hard to configure. ( apparently )
Besides the fact that lux capacitors bypass claims ( griefprevention )
Besides the fact that leafblowers bypass claims ( griefprevention )
Besides the fact that attempting to recolor the powerfist usually disconnects you XD.

Thanks! found it! minecraft/config/machinemuse/powersuits.cfg
Its a duplicate file, took forever to find.
Its still odd that these BOTH in one way or another can control the mod though, counter-intuitive....
Further Shenanigans!
The B:Leafblower=true line is missing from the machinemuse.cfg so you still cant properly nix it.
The fix is copying B:Leafblower=false from the first file in to the second file to properly disable it.